Help with New Cam
02-02-2009, 06:58 AM
#1
10 Second Club
Thread Starter
Join Date: Jun 2004
Posts: 384
Likes: 0
Received 0 Likes
on
0 Posts
Help with New Cam Hi guys
i am looking for a recomendation for a new Camshaft for my vette as you know its an 346CI Lingenfelter twin turbo 6 speed manual i have just upgraded the turbos from GT2871 to GT3076 and i am looking for more hi RPM power the cam I think it is (LPE GT2 ??? not sure) that is on my car tends to start dieng at about 5800RPM i am looking for a cam that can keep me going at least tell 6700RPM
i think my cam spics are
Cam Number Duration @ .050 Valve Lift Rocker Arm Centerline LSA
LS1-GT2-3 207 / 220 .571" / .578" 1.7 ratio 118.5
i feel i am driving a truck not a sports car i need some more hi end
your recomendation is highly apresiated
i am looking for a recomendation for a new Camshaft for my vette as you know its an 346CI Lingenfelter twin turbo 6 speed manual i have just upgraded the turbos from GT2871 to GT3076 and i am looking for more hi RPM power the cam I think it is (LPE GT2 ??? not sure) that is on my car tends to start dieng at about 5800RPM i am looking for a cam that can keep me going at least tell 6700RPM
i think my cam spics are
Cam Number Duration @ .050 Valve Lift Rocker Arm Centerline LSA
LS1-GT2-3 207 / 220 .571" / .578" 1.7 ratio 118.5
i feel i am driving a truck not a sports car i need some more hi end
your recomendation is highly apresiated
02-07-2009, 03:04 AM
#7
10 Second Club
Thread Starter
Join Date: Jun 2004
Posts: 384
Likes: 0
Received 0 Likes
on
0 Posts
hi after asking some quistions to LPE thye came back to me with these numbers what do you guys think ????
(The numbers are 228/232 588/595 with a 118 lobe seperation and a 1.7 rocker ratio. You will also have to upgrade your valve springs. For this we recommend the Comp Cams 921 springs (more installed height will also be required).
(The numbers are 228/232 588/595 with a 118 lobe seperation and a 1.7 rocker ratio. You will also have to upgrade your valve springs. For this we recommend the Comp Cams 921 springs (more installed height will also be required).
Trending Topics
02-08-2009, 02:10 AM
#9
8 Second Club
iTrader: (1)
Join Date: Nov 2001
Location: the not so stock tribe
Posts: 3,697
Likes: 0
Received 0 Likes
on
0 Posts
that cam is considered a stock cam if you ask me 
anything with less than .640 lift and 250 duration is not worth changing to and will make you gay
( plus only kids drive 347 cid engines
)
anything with less than .640 lift and 250 duration is not worth changing to and will make you gay
( plus only kids drive 347 cid engines
)
02-08-2009, 03:40 AM
#11
8 Second Club
iTrader: (1)
Join Date: Nov 2001
Location: the not so stock tribe
Posts: 3,697
Likes: 0
Received 0 Likes
on
0 Posts
think bigger is better if you go with a big enough cam you won't have to change it when you get a 427 down the road ,,, which makes it an efficient cam
if you go with a big enough cam you won't have to change it when you get a 427 down the road ,,, which makes it an efficient cam
02-08-2009, 04:00 AM
#13
8 Second Club
iTrader: (1)
Join Date: Nov 2001
Location: the not so stock tribe
Posts: 3,697
Likes: 0
Received 0 Likes
on
0 Posts
seriously , i think the duration is a bit low. and to help the valve springs last longer i would go with a bit lower lift . what do you guys think ?? ( his is a daily driver / street car, not all out race)
02-08-2009, 06:10 AM
#14
9 Second Club
EPP's FI cam would probably work well too although with a slightly lumpy idle. 232/240 on 115
02-08-2009, 06:16 AM
#15
Here is my $0.02. The split in the duration is a little big. Personally I would try to keep it in the range of 8 to 12 degrees. For a 346 CID motor, the low 230s is about the most duration you would want for a street car. Even with a wide LSA, there is going to be a bit of lope in 346. For LSA, try to keep it between 115 and 118 IMO. On turbo cars, the wider LSA is going to affect spool time since there will be less time both valves will be open during the end of the exhaust stroke and starting of the intake stroke, The exhaust gases are not going to be having the extra little helping hand out by the compressed intake charge coming in. I think the lift on the cam is way too big with out know the flow rate of the heads. Most heads peak out around 0.600" of lift and fall off quickly. If the heads do not flow well at the 0.650" range they will become a restriction even on FI applications.
02-08-2009, 11:10 AM
#16
Hmm I didn't want too much lift but wanted a bit more than the gt7 came with. I wanted smooth idle and it has that for sure. The lift with my 1.8 rockers is around 590 range ,wanted to stay under 600 so don't get valve float under boost and so don't have to change out springs as often.
The duration is a pretty broad spread and the exhaust lift is lower than intake but ling has used this cam for long time on just about everyone of their turbo builds even on bigger engines. And those engines have no problems turning higher rpms.
My current combo seems to easily rev to 6500 and might go to 7000 occasionally if need to get mph I want depending on what tires I run. Think current cam can do it.
I do see think trend to tighter duration splits and bit more bigger exhaust durations.
So wonder if ling will start installing more of the cam with the specs you said they recommended. I figure they know a thing or two about turbo cars but it also seems just about any cam can work on FI ,We really need to see some direct comparisons on dyno with the various theories tested. No split,reverse split and normal split all have their cheerleaders. More lift is usually a given that it will be better but too much lift can give valve float under boost and require those frequent spring changes, a pain on the f body with half the engine under the cowl.
Lsa usually you want to go higher to get smooth idle and thought to keep the boost in but still see proponents of like under 115 lsa too. Again would like to see some actual dynos of this stuff to really prove these theories.
The duration is a pretty broad spread and the exhaust lift is lower than intake but ling has used this cam for long time on just about everyone of their turbo builds even on bigger engines. And those engines have no problems turning higher rpms.
My current combo seems to easily rev to 6500 and might go to 7000 occasionally if need to get mph I want depending on what tires I run. Think current cam can do it.
I do see think trend to tighter duration splits and bit more bigger exhaust durations.
So wonder if ling will start installing more of the cam with the specs you said they recommended. I figure they know a thing or two about turbo cars but it also seems just about any cam can work on FI ,We really need to see some direct comparisons on dyno with the various theories tested. No split,reverse split and normal split all have their cheerleaders. More lift is usually a given that it will be better but too much lift can give valve float under boost and require those frequent spring changes, a pain on the f body with half the engine under the cowl.
Lsa usually you want to go higher to get smooth idle and thought to keep the boost in but still see proponents of like under 115 lsa too. Again would like to see some actual dynos of this stuff to really prove these theories.
